Magnetic smart polymer gel with directional plugging for conformance control in oil reservoirs

Polymer gel technology has been proven to be one of the most effective methods for conformance control and enhanced oil recovery. However, to effectively gel highly permeable layers, precise placement of the gelant within the formation is required Herein, to make the most use of polymer gel in conformance control, a novel magnetic smart polymer gel consisting of polyacrylamide and Fe3O4@polyethylenimine, is designed and prepared as a conformance fluid to achieve directional plugging in target reservoirs. To deeper understanding of the properties of Fe3O4@polyethylenimine and smart gel, as well as how they are formed and function, the microstructure of these materials was characterized through various techniques, including analysis of their crystal and chemical structures, micromorphology, and cross-linking mechanism, et al. The rheological tests suggest that the system has good viscosity and elasticity, and the gel strength can reach 105,463 mPa⋅s after aging 30 days at 120 °C. Furthermore, the controlled manipulation indicated that smart gel can move quickly and repeatedly to a designated location under a magnetic field. Additionally, the influence of the magnetic generator on the intelligent plugging performance of the smart gel system is also explored. It has been found that magnetic plugging can extend the effective lifespan of smart gel. Finally, the conformance control performance of the smart gel system is revealed by the parallel cores flow experiment. This work presents a novel smart gel system designed for directional plugging, to enhance conformance control in high-temperature oil reservoirs.